To the Editor.
—The report by the Centers for Disease Control and Prevention (CDC) on transmission of nosocomial legionnaires disease1 documents failure to eradicate Legionella organisms from the water distribution systems of 2 hospitals despite the use of hyperchlorination, thermal disinfection, and/ or metal ionization.The efficacy of these decontamination methods can be compromised by a variety of factors. The duration of thermal decontamination (160°F/71°C at the tap) used in hospital Y was only 5 minutes. The original report on the use of this method specified a 30-minute flush at the tap.2 Thus, failure to maintain the elevated temperature for a sufficient period undoubtedly contributed to this failure to eradicate Legionella. In fact, when one California hospital applied thermal eradication with a flush time of 5 minutes, as recommended by the CDC, distal site colonization by Legionella organisms was unaffected. When the process was repeated using a 30-minute flush
Stout JE, Yu VL. Eradicating Legionella From Hospital Water. JAMA. 1997;278(17):1404. doi:10.1001/jama.1997.03550170034024